Automatic leveling system for automotive headlamps

Abstract

An automatic leveling system has a headlamps optical axes L adapted to tilt vertically relative to a body of a vehicle by driving actuators 10 , a control part 16 for controlling the driving of the actuators 10 , a vehicle speed sensor 12 , a vehicle height sensor 14 and a storage part 20 for storing pitch angle data detected by the vehicle height sensor 14 . The control part 16 controls the actuators 10 based on a detected pitch angle such that the optical axes L of the headlamps are inclined to a predetermined angle relative to the road surface.

What is claimed is:  
     
       1. An automatic leveling system for automotive headlamps comprising: 
       headlamps optical axes adapted to tilt vertically relative to a body of a vehicle;  
       control means for controlling actuators to correct the tilt of the optical axes;  
       vehicle speed detecting means for detecting speeds of the vehicle;  
       pitch angle detecting means for detecting pitch angles of the vehicle; and a storage part for storing pitch angle data of the vehicle detected by said pitch angle detecting means;  
       wherein said control means is configured to control said actuators based on pitch angle not influenced by a change in posture of the vehicle resulting when the vehicle starts.  
     
     
       2. The automatic leveling system for automotive headlamps as set forth in  claim 1 , wherein if the start of the vehicle is detected by said vehicle speed detecting means within a predetermined set time after a control of said actuators is carried out, said control means determines that said control and the start of the vehicle substantially coincide with each other. 
     
     
       3. The automatic leveling system for automotive headlamps as set forth in  claim 2 , wherein said predetermined set time is equal to or longer than an interval of time between the depression of an accelerator pedal and the detection of the start of said vehicle. 
     
     
       4. The automatic leveling system for automotive headlamps as set forth in  claim 1 , wherein if the actuators have been controlled more than once before they are controlled at the time of the start of the vehicle, pitch angle data detected before the start of the vehicle are used for controlling the actuators. 
     
     
       5. The automatic leveling system for automotive headlamps as set forth in  claim 1 , if the actuators are controlled for the first time, pitch angle data which is detected just previous to the depression of the accelerator pedal while the vehicle is at a stop is used for controlling the actuators. 
     
     
       6. The automatic leveling system for automotive headlamps as set forth in  claim 1 , if the actuators are controlled for the first time and no pitch angle is detected previous to the depression of the accelerator pedal, said actuators are prevented from being driven. 
     
     
       7. The automatic leveling system for automotive headlamps as set forth in  claim 1 , wherein said storage part is configured such that older pitch angle data are replaced with newer pitch angle data in the order stored when latest pitch angle data are entered to update the pitch angle data. 
     
     
       8. The automatic leveling system for automotive headlamps as set forth in claims  1 , wherein controlling the driving of said actuators is carried out on condition that said headlamps are illuminated. 
     
     
       9. The automatic leveling system for automotive headlamps as set forth in  claim 1 , wherein an interval at which said actuators are driven is configured such that said interval becomes longer than a maximum driving time of said actuators needed to perform a single leveling.